Expanding mandrel.



G. RILEY.

EXPANDING MANDREL.

APPLICATION FILED APR. 4. 1918.

1,280,846 Patented Oct. 8, 1918.

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wmem George Riley v attorneys GEORGE RILEY, 0F MORENCI, ARIZONA.

EXPANDING MANDREL.

Specification of Letters Patent.

Patented Oct. 8, 1918.

Application filed April 4, 1918. Serial No. 226,691.

To all whom it may concern:

Be it known that I, GEORGE RILEY, a citizen of the United States, and a resident of Morenci, in the county of Greenlee and State of Arizona, have invented certain new. and useful'Improvements in Expanding Mandrels, of which the following is a specification.

My invention is an improvement in expanding mandrels, and has for its object to provide a device of the character specified adapted for use in lathes and the like, wherein a central spindle is provided having'intermediate its ends a portion rectangular in cross section and tapering from one end to the other, together with a series of shoes adapted to fit and engage the said portion and to be expanded and contracted by moving the said shoes longitudinally of the said portion, the said shoes having a particular conformation for the purpose specified.

In the drawings:

Figure l is a side view of the improved mandrel shown in connection with a lathe;

Fig. 2 is a top plan view of the mandrel;

Fig. 3 is a perspective view of the shoes detached; and

Fig. 4 is an end view of the mandrel.

In the present embodiment of the invention, a shank 1 is provided, having intermediate its ends a portion 2 which is substantially square in cross section, the corners of the said portion, however, bein beveled as shown. With this surface is adapted to cooperate a series of similar shoes 3, the said shoes being similar, and each being angular in cross section, and consisting of two plane portions extending at a right angle with respect to each other.

Each of these portions is rabbeted, as indicated at 4:, at one end and at the opposite end from the rabbet of the other portion, and the extension 5 formed by the rabbet at the opposite end from the rabbet is adapted to engage within the rabbeted portion of the ad acent shoe. Each shoe 3 thus engages a corner of the square portion of the mandrel, and it will be obvious that the interengaging tongues and rabbets prevent longitudinal movement of the shoes with respect to each other.

The shoes constitute the expanding portion of the mandrel, and the said shoes are of such size that at the small end of the mandrel they will fit the mandrel, engaging or approximately engaging at their adjacent notches are adapted to receive a ring 8 for 1 holding the shoes on the mandrel durmg the placing of the mandrel in the article to be turned or supported.

The shank also has its ends recessed, as indicated at 9, in order that it may be placed 1 between centers of a lathe or grinder or similar machine, and at one end has a tapered portion 10 to permit the mandrel to be placed in the head of the lathe or grinder. There is also a polygonal surface 11 adjacent to the tapered portion so that a suitable drive may be provided to prevent the shank turning when taking a heavy cut. The square portion of the shank provides oppositely arranged parallel surfaces which diverge toward one end of the mandrel, so that when the shoes which have cooperating surfaces are moved along these surfaces they will be gradually moved away from each other. The improved mandrel may be engaged with a square hole or with a round hole, and in either case the Work will be accurately centered when the mandrel is placed in the lathe.

The improved mandrel is long lived and there are no delicate parts to become broken. The bore of the article to be worked upon is almost filled with the mandrel and, therefore, heavy cuts may be taken without danger of chattering or slipping. It will be evident that the shape and design may be changed without departing from the scope of the invention as set forth in the appended claims.

I claim:

1. An expanding mandrel comprising a shank having intermediate its ends a portion square in cross section and gradually increasing in cross section from one end to the other, and a series of shoes fitting upon the said portion and adapted to be moved away from each other when they are moved longitudinally of the said portion toward the large end of the same, each of the said shoes consisting of two portions extending at a right angle with respect to each other and adapted to engage a corner of the said portion, each of the said portions of each shoe being rabbeted at one corner and at the opposite corner from the other portion of the said ,shoe, and the rahbeted portions interengaging to guide the shoes in their expanding movement, each shoe having a notch intermediate its ends and a resilient ring for .engaging the notches to hold the shoes in place on the shank.

'2. An expanding mandrel comprising a shank having intermediate cits ends a portion square in cross section and gradually increasinggin crosssection from one rend-to :the other, and a series of shoes ifitting upon the said portion and adapted to :he moved away from-each other when they 2,3116 {IHOVBd longitlldinally'of the said portion "toward %the large end of the same, each of the-saidshoes consisting of two :portions extending at a right angle with respect to each other :and adapted to engage a connergof the-said portion, each of thesaid portions of each shoe heingrrabbeted atone corner and at the apposite corner from the other portion of the said shoe, and the rabbeted portions interengaging to gu'idethe shoes in their expanding movement.

3'. An expanding mandrel comprising a shank having intermediate its ends a portion square in cross sectlon and tapering, and a series of shoes :fitting upon the said portion of the square portion, eaolh shoe being nabbeted atteaoh side edge, therabhete'd portions of ztheshoes interengaging 1'00 guide the shoe in their, expanding movement. 7 V

GEORGE RILEY.

Witnesses: v

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